AP process

[Tahmoures]

Hello to all.
I want to learn about AP process but I can't find the right threads or sources to learn about. Can somebody help me?

I used to use nitric acid for dissolving base metals but its too hard to control NOx fumes so I wanna make a change.

Best regards
Tahmoures

 

[MicheleM]

Hello, the AP process is a "misnomer " for a CuCl2 (aq) . CuCl2 is able to dissolve copper and almost all base metal leaving gold foils/dust ecc.
how to make CuCl2?:
The simplest way is put together Cu, HCl plus an oxider such as the atmospheric oxygen.
A good oxydizer is H2O2 ( from this the misnomer "Acid/Peroxide process).

 

[Martijn]

This pdf explains it in detail.
Basically you make copper 1 chloride, convert into copper 2 chloride with air, which eats copper and gets reduced to copper 1 chloride, the continuous air turns it back to copper 2 chloride, and so on. It can be reused over and over and is not waste until you have too much.
All the solution needs is some free HCl and air bubbled through to keep it going. Once white green slime is forming you need to add HCl.
To start, use copper oxide(red or black) or copper carbonate(green like those copper roofs) and add HCl.
If you use H2O2 to make the starter CuCl2 do so with pure copper without gold. To prevent any gold going in solution.

Martijn.
Edited for spelling

 

[kurtak]

Also - a little more about HCl + H2O2 (for better understanding)

https://goldrefiningforum.com/threads/ap-questions.32347/#post-343123
Kurt

 

[kurtak]

I used to use nitric acid for dissolving base metals but its too hard to control NOx fumes so I wanna make a change.

It does not really matter whether you use nitric or HCl - you still have to deal with the fumes - they both expel fumes into the air as soon as you open the bottle & about the same amount of fumes - they are just different kinds of (acidic) fumes --- you just don't see the HCl fumes as much because they are white/clear compared to the brown fumes you see when dissolving metal with nitric

Fumes from nitric = NOx

Fumes from HCl = Cl2 (chlorine)

Both are toxic

Kurt

 

[kurtak]

Here is a true story about HCl fumes

A guy had a bunch of gold plated SS (stainless steel)

He put some of it in a 5 gallon bucket & then put enough HCl in the bucket to cover the gold plated SS & put the lid on the bucket

A few hours later he went to check on it & see how it was going

When he took the lid off the bucket to have a look - the fume hit him in the face which took his breath away when he breathed them in but they also got in his eyes & blinded him - which knocked him to the ground

He was near blind & having trouble breathing & had to crawl on his hands & knees to the house next door to get help (someone to call 911)

He spent something like the next 12 - 16 hours in the hospital on oxygen & having his eyes washed out with LOTS of water

He then called me - about a week later - after he had recovered - to see if I would process his gold plated SS

I did & I recovered 50 plus grams gold for him

Bottom line - he learned - the hard way - that HCl fumes are dangerous - just as dangerous as nitric fumes

Kurt

 

[MicheleM]

Mmm HCl is a gas at room temperature and standard pressure, what we called chloridric acid is HCl dissolved in H20